Sprites at Paranal Observatory

Amazing image of sprites at Paranal Observatory, captured from the VLT platform by ESO Photo Ambassador Petr Horálek.

Sprites are extremely rare atmosphere phemomena caused by irregularities in the ionosphere, high above storm clouds, at altitudes of about 80 kilometres. Typically seen as groups of red-orange flashes, they are triggered by positive cloud-to-ground lightning, which is rarer and more powerful than its negative counterpart, as the lightning discharge originates from the upper regions of the cloud, further from the ground. In a short burst, the sprite extends rapidly downwards, creating dangling red tendrils before disappearing.

The sprite pictured here was most likely over 500 kilometres away (compare with a satellite image showing the storm over Argentina), spanned a height of up to 80 kilometres and lasted only a fraction of a second.